(1) Field of the Invention
This invention relates to a slide vane type compressor suitable for use with an air conditioning system for an automotive vehicle, a room air conditioning system, a freezer, etc.
(2) Description of the Prior Art
Slide vane type compressors are well known, as disclosed in U.S. Pat. Nos. 4,050,263 and 4,103,506, for example.
A slide vane type compressor generally comprises a cam ring with a space of the elliptic shape interposed between a front plate and a rear plate connected to opposite sides of the cam ring, a rotor formed with a plurality of vane grooves and located in the space of the cam ring and journalled at its shaft portion by bearings mounted in the front and rear plates, and a plurality of vanes each slidably inserted in one of the vane grooves of the rotor.
In this type of compressor, the terminal point angle of a suction port or the angle formed by the point at which the outer peripheral surface of the rotor becomes closest to the inner peripheral surface of the cam ring and the terminal point of the suction port (terminal point as viewed in the direction of rotation of the rotor) is equal to the geometrical terminal point angle decided geometrically based on the number of vanes and the number of working chambers (the number of working chambers defined between the rotor and the cam ring when the vanes are not inserted in the rotor).
This type of compressor of the prior art would suffer the disadvantage that it would be impossible to secure a cross-sectional area of suction sufficient for handling a volume of fluid flowing through the suction ports. Thus, the flow velocity of the gas flowing through the suction ports would increase and give rise to the problem that the volumetric efficiency of the compressor is reduced and the discharged gas has an elevated temperature.